The institutional detergent market distributes a variety of products for washing silverware, pots and pans, dishes, floors, walls, stainless steel surfaces, tile and other areas.
Unlike products used in the home, institutional detergents are often sold in bulk and dispensed from mechanical dispensers. There are a variety of different physical forms these can take, including liquids, powders, solidified bricks, granules and tablets. Several factors enter into the determination of which particular physical form is most suitable for the desired application.
Feed rate is a very important consideration. With a liquid, where the product is directly injected for use, use concentration is easy to control. Unfortunately with liquids, the concentration is generally relatively low and therefore the container size can be prohibitively large. With solid forms, which are dissolved with water, the rate of dissolution can determine feed rate.
Maintaining consistency of the product is very important. With a brick formulation, the product consistency can be maintained to a certain extent, but dissolution rate can be slow and, as with many forms, there may also be problems with disposing of the container.
Another very important factor in distributing institutional detergents is packaging. For environmental reasons, it is preferable to minimize packaging. U.S. Pat. No. 5,078,306 discloses a bag of detergent tablets wherein the bag is a water soluble material. This product is apparently designed to minimize packaging, but has several significant disadvantages. Primarily, with a water soluble bag, the water will act to dissolve the plastic bag. However, the undissolved residue of such bags tend to clog the dispenser. Also with a water soluble bag, there is the requirement of an exterior overwrap to prevent humidity or extraneous water from destroying the water soluble bag during shipping and storage.
All of these problems are compounded with highly hygroscopic (highly caustic) and/or hydratable materials. Of course, with the caustic materials, the operators should never physically handle the detergent. Powdered cleaning compounds are typically dispensed with water. Given that premature exposure to water tends to increase the caking tendency of powders, clogging of the dispenser and uniform dispensing from powder systems, especially those prone to prolonged periods of inactivity, may be a problem.
Another significant feature, with respect to hydratable detergents, is the mass and size of the detergent. If fully hydrated detergents are used in lieu of the anhydrous detergent, the mass and volume of the detergent will increase relative to the activity level. This, in turn, increases the shipping expenses. The dispenser also needs to be larger. Accordingly, it is preferable to use a detergent which has very little water of hydration.
Many detergents, particularly highly caustic detergents, dissolve in water and liberate a great deal of heat. It is therefore preferable to control the dissolution rate of these detergents to avoid temperature peaks in the dispensing equipment.